<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>
        * {
            padding: 0;
            margin: 0;

        }

        .wrapper {
            width: 800px;
            margin: 10px auto;
            border: 2px solid #ccc;
            text-align: center;
        }

        .lucking {
            width: 200px;
            height: 180px;
            border: 1px solid #000;
            position: relative;
        }

        .lucking img {
            position: absolute;
            left: 0;
            bottom: 0;
        }

        .wrapper ul li {
            width: 100px;
            height: 50px;
            line-height: 50px;
            text-align: center;
            margin: 4px;
            border: 2px solid #ccc;
            border-radius: 5px;
            /* 不设置float:left的原因
            1： 浮动不能让父盒子撑开高度 
            2： display:inline-block 具有行内元素的属性特征，给父盒子加text-align:center 可使其居中
            */
            display: inline-block;
        }

        .wrapper button {
            margin-top: 20px;
            width: 80px;
            height: 40px;
            border: none;
            background-color: #ddd;
            border-radius: 5px;
            font-weight: 700;
            outline: none;
            cursor: pointer;
        }

        .wrapper .active {
            /* background-color: #f1084a; */
            background-color: yellow;
            font-weight: 700;
        }
    </style>
</head>

<body>
    <h2 align="center">召唤皮卡丘系统</h2>
    <div class="wrapper" id="_wrapper">
        <ul id="_ul"></ul>
        <button class="start">开始点名</button>
        <button class="stop">停止</button>
        <div class="lucking" id="_lucking">
            <p></p>
            <img src="pkq.jpg" alt="">
        </div>
    </div>
</body>

</html>
<script>
    var array = [
        '谈旭',
        '肖扬',
        '赵寰宇',
        '贺正武',
        '刘皓伟',
        '胡鑫宇',
        '王天粹',
        '周宣霖',
        '彭家楠',
        '周子健',
        '卢环',
        '罗杲瑞',
        '熊国初',
        '黄如豪',
        '蒋康',
        '李佳',
        '蒋荣武',
        '刘洋涛',
        '邹谈',
        '刘勃君',
        '邓林辉',
        '王旋',
        '何辰',
        '钟杰',
        '周鹏辉',
        '欧志国',
        '谢贤润',
        '李剑',
        '桂铮',
        '张明',
        '罗尧文',
        '汤杰',
        '李鑫',
        '沈林云',
        '何利葵',
        '兰金帅',
        '李志明',
        '田勇',
        '吴呈城',
        '王乐',
        '王爱良',
        '蒋斌媛',
    ];
    // 获取元素
    var _wrapper = document.getElementById('_wrapper');
    var ul = document.getElementById('_ul');;
    var timer = null;
    init();

    function init() {
        // 动态创建li
        for (var i = 0; i < array.length; i++) {
            var oli = document.createElement('li');
            oli.innerHTML = array[i];
            ul.appendChild(oli);
        }
        // 点击
        click();
    }
    function click() {
        // 获取start按钮
        var start = _wrapper.getElementsByTagName('button')[0];
        var stop = _wrapper.getElementsByTagName('button')[1];
        var lucking = document.getElementById('_lucking');
        // 定时器
        start.addEventListener('click', function () {
            clearInterval(timer);
            timer = setInterval(function () {
                // 获得随机数
                var random = Math.floor(Math.random() * array.length);
                for (var i = 0; i < array.length; i++) {
                    ul.children[i].className = '';
                }
                ul.children[random].className = 'active';
                // 50
            }, 30);
        });
        stop.addEventListener('click', function () {
            clearInterval(timer);
            // 找到此时的元素
            var active = document.getElementsByClassName('active')[0];
            lucking.children[0].innerText = "出来吧：" + active.innerText;
        })
    }
</script>